1. Field of the Invention
The present invention relates to endoscopic devices, and, more particularly, to a sheath, external to an endoscope, that includes working channels capable of controllable deflection at their distal ends, and to a related method of using the sheath during an endoscopic operation.
2. Background of the Related Art
An endoscope is a flexible medical device for insertion into a body passageway or cavity that enables an operator, positioned at a remote external location, to perform certain surgical procedures at a site internal to the patient's body. In general, an endoscope includes a long flexible tubular member equipped with, for example, a miniature viewing device, an illumination device, and working channels. The endoscope has a proximal end that remains external to the patient and a distal end having an endoscope tip for insertion into a body cavity of the patient.
A typical endoscope 10 is illustrated in FIG. 1. An illumination device of endoscope 10 typically includes a lens 16 at an endoscope tip 14. Lens 16 is positioned proximate to a viewing device 17. Light emanates from lens 16 to enable viewing device 17 to capture images in the in the body cavity and electrically or optically transmit the images through a tubular body 13 of endoscope 10 for display at an external monitor. Once viewing the transmitted images, the endoscope operator may insert one or more surgical instruments through working channels 18, 20 to perform an endoscopic procedure at the internal body cavity site. These endoscopic procedures may include, for example, snare resections, injections, or biopsies of particular internal areas of the patient's body.
Often, these endoscopic procedures require the use of multiple endoscopic instruments working in cooperation, where each instrument inserts through a separate working channel. Because these instruments work in cooperation, their maneuverability at the endoscope tip is critical to the success of the surgical procedure. But, this maneuverability is limited by the diameter constraints of the endoscope tip which, in turn, are dictated by the particular body cavity dimensions of the patient. Endoscope designs have evolved to minimize the diameter of the endoscope tip to limit the discomfort experienced by the patient. These designs, however, have failed to maximize the maneuverability of therapeutic devices at the endoscope tip. For example, the working channel of the conventional endoscope remains coexistent with the endoscope and offers no independent motion in relation to the endoscope. Such a limitation impedes the maneuverability of surgical instruments at the operation site since they are constrained to follow the movement of the endoscope.
With reference once again to FIG. 1, working channels 18, 20 of endoscope 10 are located internal to endoscope 10, positioned in close proximity to one another, and fixed in the endoscope with no independent mobility. In essence, working channels 18, 20 simply provide a passage for the surgical instruments to reach endoscope tip 14. Because working channels 18, 20 are fixed and located in such close proximity to one another, the endoscope operator has limited range of motion over the surgical instruments at the operation site. This limited mobility not only hinders the cooperation -between the multiple surgical instruments but also inhibits the potential for advancement into more complex endoscopic procedures.
Consequently, there is a need for an endoscopic device with working channels that, in addition to providing a passage for the surgical instruments, optimizes the mobility of the surgical instruments at the operation site, while maintaining the required dimensional constraints to permit travel of the endoscopic device through the body cavities of the patient.